A Perturbative Approach to the Relativistic Harmonic Oscillator

A quantum realization of the Relativistic Harmonic Oscillator is realized in terms of the spatial variable $x$ and {\d\over \d x} (the minimal canonical representation). The eigenstates of the Hamiltonian operator are found (at lower order) by using a perturbation expansion in the constant $c^{-1}$. Unlike the Foldy-Wouthuysen transformed version of the relativistic hydrogen atom, conventional perturbation theory cannot be applied and a perturbation of the scalar product itself is required.Comment: 9 pages, latex, no figure

Analisis Teknis Dan Finansial USAha Perikanan Tangkap Payang Di Pelabuhan Perikanan Pantai (Ppp) Wonokerto Kabupaten Pekalongan

Produksi perikanan di PPP Wonokerto terus mengalami peningkatan dari tahun ke tahun, dimana alat tangkap Payang merupakan salah satu alat tangkap yang dominan di PPP Wonokerto. Dengan demikian, perlu diketahui seberapa jauh kegiatan perikanan payang masih dapat berjalan dengan layak untuk diusahakan.Tujuan penelitian ini adalah mengetahui aspek teknis USAha perikanan tangkap payang dan menganalisis tingkat kelayakan USAha dari segi finansial dengan menghitung NPV, IRR, B/C Ratio dan PP. Penelitian ini dilaksanakan pada bulan Mei 2015. Metode penelitian yang digunakan adalah metode studi kasus deskriptif. Metode pengambilan sampel yang digunakan adalah purposive sampling. Metode analisis data yang digunakan adalah analisis teknis dan analisis finansial. Pengambilan data primer dilakukan dengan cara pengukuran, observasi langsung dan wawancara, sedangkan pengambilan data sekunder dilakukan dengan mengambil data dan informasi dari instansi-instansi yang mendukung penelitian. Hasil penelitian menunjukkan bahwa alat tangkap payang yang di operasikan di perairan Wonokerto memiliki ukuran mata jaring (mesh size) 2 – 15 inchi, dengan hasil tangkapan ikan pelagis. Analisis finansial USAha perikanan tangkap payang didapatkan nilai NPV Rp 470.706.068; IRR 36 % ;PP 1,15 tahun; dan B/C ratio 1,25 yang berarti bahwa USAha perikanan tangkap payang di PPP Wonokerto layak secara finansial. Fish production in PPP Wonokerto continues to increase from year to year, which Payang fishing tool is one of the dominant fishing equipment in PPP Wonokerto. Therefore, needed to know how much payang fishing activity still be able to walk properly to be applied. This research purpose is to know the technical aspects of the payang fishery business and analyze the feasibility of financial terms to calculate NPV, IRR, B / C Ratio and PP. This study was conducted in May 2015. The method used was the descriptive case study method. The sampling method used was purposive sampling. Data analysis method used was the analysis of the technical and financial analysis. Primary data collection was done by measuring, direct observation and interviews, while secondary data collection was done by taking the data and information from agencies that support research. The results showed that the payang fishing equpment that operated in Wonokerto waters have a mesh size 2-15 inches, with catches of pelagic fish. Financial analysis to payang fishing obtained NPV value of Rp 470 706 068; IRR 36%; PP 1.15 years; and B / C ratio of 1.25, which means that the payang fishery business in PPP Wonokerto financially feasible

Some Orthogonal Polynomials Arising from Coherent States

We explore in this paper some orthogonal polynomials which are naturally associated to certain families of coherent states, often referred to as nonlinear coherent states in the quantum optics literature. Some examples turn out to be known orthogonal polynomials but in many cases we encounter a general class of new orthogonal polynomials for which we establish several qualitative results.Comment: 21 page

Forces between functionalized silica nanoparticles in solution

To prevent the flocculation and phase separation of nanoparticles in solution, nanoparticles are often functionalized with short chain surfactants. Here we present fully-atomistic molecular dynamics simulations which characterize how these functional coatings affect the interactions between nanoparticles and with the surrounding solvent. For 5 nm diameter silica nanoparticles coated with poly(ethylene oxide) (PEO) oligomers in water, we determined the hydrodynamic drag on two approaching nanoparticles moving through solvent and on a single nanoparticle as it approaches a planar surface. In most circumstances, acroscale fluid theory accurately predicts the drag on these nano-scale particles. Good agreement is seen with Brenner's analytical solutions for wall separations larger than the soft nanoparticle radius. For two approaching coated nanoparticles, the solvent-mediated (velocity-independent) and lubrication (velocity-dependent) forces are purely repulsive and do not exhibit force oscillations that are typical of uncoated rigid spheres.Comment: 4 pages, 3 fig

miRNAs as Regulators of Antidiabetic Effects of Fucoidans

open access articleDiabetes mellitus is a metabolic disease with a high mortality rate worldwide. MicroRNAs (miRNAs), and other small noncoding RNAs, serve as endogenous gene regulators through binding to specific sequences in RNA and modifying gene expression toward up- or down-regulation. miRNAs have become compelling therapeutic targets and play crucial roles in regulating the process of insulin resistance. Fucoidan has shown potential function as an a-amylase inhibitor, which may be beneficial in the management of type 2 diabetes mellitus. In recent years, many studies on fucoidan focused on the decrease in blood glucose levels caused by ingesting low-glucose food or glucose-lowering components. However, the importance of miRNAs as regulators of antidiabetic effects was rarely recognized. Hence, this review emphasizes the antidiabetic mechanisms of fucoidan through regulation of miRNAs. Fucoidan exerts a vital antidiabetic effect by regulation of miRNA expression and thus provides a novel biological target for future research

Impact of localization on Dyson's circular ensemble

A wide variety of complex physical systems described by unitary matrices have been shown numerically to satisfy level statistics predicted by Dyson's circular ensemble. We argue that the impact of localization in such systems is to provide certain restrictions on the eigenvalues. We consider a solvable model which takes into account such restrictions qualitatively and find that within the model a gap is created in the spectrum, and there is a transition from the universal Wigner distribution towards a Poisson distribution with increasing localization.Comment: To be published in J. Phys.

Pengaruh Pelumasan Terhadap Deformasi Plastis Pada Kontak Dua Benda

Running-in adalah suatu cara yang efektif untuk penyesuaian kontak dua komponen dalam situasi fungsional rolling dan atau sliding. Ada banyak Perubahan parameter selama running-in, kimiawi atau mekanis. Namun, Perubahan geometri-mikro karena keausan atau deformasi plastis dominan. Ketika dua permukaan benda padat saling menekan selalu akan terjadi deformasi kontak. Sebagai konsekuensi alami suatu interaksi dua permukaan yang saling bergerak relative akan berlangsung gesekan dan keausan antar muka. Gesekan dan keausan bukanlah sifat material, tetapi sifat sistem, tergantung material yang digunakan dan kondisi pengoperasian. Paper ini membahas deformasi plastis pada kontak dua benda kaitannya dengan pengaruh kondisi tanpa pelumasan dan menggunakan pelumas. Dalam penelitian ini menggunakan 7 macam rasio radius benda kontak dan dua kondisi pelumasan. Hasil penelitian dapat dinyatakan bahwa kenaikan harga deformasi plastis untuk kondisi dengan pelumas lebih tinggi dari pada kenaikan deformasi plastis untuk kondisi tanpa pelumas. Kata kunci: Deformasi, pelumasan, rasio radius, rolling contact, running-in

A numerical investigation of mechanical response of unfilled Styrene Butadiene Rubber by static straight blade indentation

This study investigates the mechanical response of straight blade indentation on Unfilled Styrene Butadiene Rubber by Finite Element Analysis (FEA). The mechanical responses investigated were stiffness, maximum stress and indentation load. The rubber material was modeled as a hyperelastic material with the Money-Rivlin Strain Energy Function. Results were presented as a function of the blade characteristics, wedge angle and tip radius at a specified depth of indentation. Results showed that the stiffness and indenter load increase due to an increase in the wedge angle and the tip radius, on the other hand, the maximum stress decreases. Surprisingly, an approximately linear relationship between the mechanical response and the blade characteristic was found. Furthermore, the mechanical response at a specified maximum stress was also discussed

Pengaruh Pelumasan Terhadap Deformasi Plastis Pada Kontak Dua Benda

Running-in adalah suatu cara yang efektif untuk penyesuaian kontak dua komponen dalam situasi fungsional rolling dan atau sliding. Ada banyak Perubahan parameter selama running-in, kimiawi atau mekanis. Namun, Perubahan geometri-mikro karena keausan atau deformasi plastis dominan. Ketika dua permukaan benda padat saling menekan selalu akan terjadi deformasi kontak. Sebagai konsekuensi alami suatu interaksi dua permukaan yang saling bergerak relative akan berlangsung gesekan dan keausan antar muka. Gesekan dan keausan bukanlah sifat material, tetapi sifat sistem, tergantung material yang digunakan dan kondisi pengoperasian. Paper ini membahas deformasi plastis pada kontak dua benda kaitannya dengan pengaruh kondisi tanpa pelumasan dan menggunakan pelumas. Dalam penelitian ini menggunakan 7 macam rasio radius benda kontak dan dua kondisi pelumasan. Hasil penelitian dapat dinyatakan bahwa kenaikan harga deformasi plastis untuk kondisi dengan pelumas lebih tinggi dari pada kenaikan deformasi plastis untuk kondisi tanpa pelumas. Kata kunci: Deformasi, pelumasan, rasio radius, rolling contact, running-in